Aberrant expression of the intracellular signaling molecule Ras Homolog Family Member H (RhoH) occurs in a number of hematopoietic disorders, such as leukemias and lymphomas. In these disorders, abnormal expression of RhoH has been shown to be a marker of poor prognosis. However, directly using RhoH as a diagnostic marker or therapeutic target is difficult since it is expressed intracellularly.